Also a quick Google search for "CNAME RFC" would have helped a lot.
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MassimoMay 26 '10 at 20:31

Should also point out (in case folks don't know) that the IETF's (Internet Engineering Task Force) RFC system define many of the internet standards, usually looking for "thing rfc" will turn up the formal specification for that thing.
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JasonMay 27 '10 at 13:48